The present invention relates generally to elevators and, in particular, to a method and a device for adjusting the distance between the decks of double-decker and multi-decker elevators.
The German patent DE 1 113 293 shows an elevator installation that consists of an elevator with two cars, one beneath the other, which together have the height of two stories. The two cars, which are caused to move by a common motor, are fastened immovably together and form a so-called double-decker elevator.
In the double-decker elevator installation described above, the two cars are joined immovably together and do not permit any change in their positions relative to each other. In this case, the distance between floors must be kept exactly the same over the entire height of the building; otherwise steps occur with one or even both of the decks when the elevator stops at a landing. The same problem arises if settlement occurs in the walls of a building months or years after it has been constructed, or if the tolerances are not adhered to, which has a particularly pronounced effect in tall buildings. A control system on a double-decker elevator of the type mentioned above is not able to cause both cars to halt in exactly the right position at the respective landings. Stopping inaccuracies, or so-called steps, occur on at least one and possibly both of the cars.